Exercise-Induced QRS Prolongation in Brugada Syndrome: Implications for Improving Disease Phenotyping and Diagnosis.

Exercise-induced QRSd prolongation is ubiquitous in BrS primarily owing to delayed right ventricular activation. This electrocardiogram phenotype predicts a positive procainamide response and may provide a noninvasive screening tool to aid in the diagnosis of BrS before drug challenge.